The present invention is related generally to a wireless communication device and, more particularly, to a system and method to detect the edge of service in a first communication system and obtain coverage in a second communication system for the wireless communication device.
Wireless communication devices, such as cellular telephones, are widely used as a replacement for and in addition to conventional telephone systems. In addition to providing the functionality of a conventional telephone, wireless communication devices offer the advantage of portability, thus enabling the user to establish a wireless communication link between virtually any two locations on Earth.
Wireless communication devices operate within regions or cells of coverage each having a geographic coverage area. A transmitter and receiver, centrally located within each cell, is controlled such that the effective coverage area of the cell just overlaps with adjacent cells. Cells for analog wireless communication devices and cells for digital wireless communication devices may not be coextensive. That is, although a given city may have complete analog cellular coverage and complete digital cellular coverage, analog and digital cell boundaries are usually different.
Typically, wireless communication devices have lower levels of performance when they are near the edge of a cell than when they are not near an edge. Therefore, when traveling from one cell to another, performance of a wireless communication device tends to degrade while approaching the edge of a first cell and does not return to full performance until the wireless communication device is away from the edge of the second cell. This is an especially important effect when the cell is on the edge of the coverage area, here there is no second cell to move into. This degradation is especially frustrating when the edge of one system""s coverage area is the beginning of another system""s coverage area. Thus, it is apparent that there is a need to increase the performance of wireless communication devices when located near the edge of a cell, and especially at the edge of a coverage area. The present invention provides this and other advantages as will be apparent from the following figures and accompanying description.
In one aspect of the present invention, a system and method to enhance performance of a mobile phone is presented. The method includes monitoring a level of performance of the mobile telephone communicating with a first service provider system, comparing the first performance level with a first threshold level and, if the first performance level remains below the first threshold level for a first duration of time, switching the telephone to a second service provider system.
In another aspect of the invention, when the mobile phone is in an idle mode, first and second performance levels are monitored. If the first performance level falls below a first threshold or the second performance level falls below a second threshold a timer is started. If both the first and second performance levels exceed their respective thresholds, the timer is reset, but if the timer runs long enough to exceed a preset time limit, the mobile telephone switches to another service provider system. If the mobile phone is a dual-mode or dual-band phone, it is possible to switch between modes or bands when switching service provider systems.